I looked at the photo in detail and I do not see the head wound mentioned in your link...

In the larger photo, you can see the cap next to his head, which looks blue to me. It also appears he is lying on a blanket, which was probably used to drag the body. The fact that his pants are unbuttoned seems to me to suggest he was wounded in the lower belly and was likely looking for the wound, which I have seen often in these old images.

There is also something in the foreground, that looks to me like a piece of broken rifle stock..